1. Field of the Invention
The present invention relates to a panel fixing structure which removably fixes a panel to a rectangular panel fixing opening provided in a housing, so as to cover the circumference of one or a plurality of interface terminals disposed inside the housing, and an information processor in which a panel is fixed by the panel fixing structure.
2. Description of the Related Art
Input and output (I/O) connectors to which external devices or the like are electrically connected are provided in a panel fixing opening formed on the back surface or the like of a housing as an external casing of a personal computer (hereinafter, referred to as a personal computer). A panel which electrically shields the input and output connectors is removably fixed to the panel fixing opening, so as to cover the circumference of the input and output connectors.
As a fixing structure which removably fixes a panel to a panel fixing opening, a panel fixing structure described in Paragraph [0022] and FIG. 4 of Japanese Patent Application Publication No. H04-233017 (Reference 1) is known. According to the panel fixing structure described in Reference 1, a plurality of projections (dependent legs in Reference 1) provided in the long side of the lower side of the square panel (shield member in Reference 1) fits the neighborhood of the edge portion of the lower surface of the panel fixing opening (bay opening in Reference 1). Then, a pair of engagement projections (spring tags in Reference 1) having a spring property, which is provided in both of the short sides of the square panel (shield member in Reference 1), is pressed into the edge portions of the panel fixing opening on both sides to be engaged therewith while bending.
In the panel fixing structure described in Reference 1, as described above, both the operation which fits the projections provided in the long side of the lower side of the square panel to the neighborhood of the edge portion of the lower surface of the panel fixing opening, and the operation, which engages a pair of the engagement projections having a spring property, which is provided in both of the short sides of the square panel, with both of the edge portions of the panel fixing opening while bending the engagement projections, are required. For this reason, the workability when fixing the panel to the panel fixing opening is inefficient.
Therefore, in order to improve the workability of panel fixing, a panel fixing structure using a panel 100 having a panel surface 100a as illustrated in FIG. 19 is known. The panel 100 includes engagement protrusions 100b, 100c formed in the edge portions of the four sides of the panel surface 100a along the longitudinal direction (in FIG. 19, the neighborhood of the edge portions of the adjacent long and short sides is illustrated). Each of the engagement protrusions 100b, 100c protrudes in the insertion direction to the panel fixing opening and has a spring property. The leading end portion of each of the engagement protrusions is bent outwardly at about 180 degrees. In addition, a plurality of semispherical projections 100d is provided in the external surface of each engagement protrusion 100b, 100c along the longitudinal direction. The leading end portion of each engagement protrusion 100b, 100c on the projection side 100d is bent outwardly, and includes a leading end locking portion 100e. 
As illustrated in FIGS. 20A, 20B, by inserting each engagement protrusion 100b, 100c of the panel plate 100 into the panel fixing opening 101, the projections 100d make contact with the inside wall surface of the panel fixing opening 101, and each engagement protrusion 100b, 100c reaches the edge portion of the inside wall surface while bending in the inside direction of the panel fixing opening 101, so that each bent engagement protrusion 100b, 100c is brought back to the original condition. The panel 100 is thereby fixed to the panel fixing opening 101 while sandwiching the panel fixing opening 101 by way of the leading end locking portions 100e and the projections 100d which are locked to the neighborhood of the edge portion of the inside wall surface opposite the insertion direction from both surfaces as illustrated in FIG. 20B.
Meanwhile, a space having a predetermined width is provided between the corner portions of the engagement protrusions 100b, 100c on the adjacent long side and short side, such that the engagement protrusions 100b, 100c do not interfere (make contact) with each other when each engagement protrusion 100b, 100c is inserted into the panel fixing opening 101 to be engaged therewith while bending.
Each of FIGS. 19, 20A, 20B schematically illustrates the shape of the space provided between the corner portions of the adjacent engagement protrusions 100b, 100c. Specifically, as illustrated in FIG. 21A, a cutting process is performed on the end portions of the adjacent engagement protrusions 100b, 100c, such that leading end corner portions 100f, 100g which are engaged with the corner portions of the inside wall surface of the panel fixing opening 101 when inserting are previously formed in a predetermined shape to be symmetric with the same length with respect to the intermediate line A in the middle of the corner portions.
If the size of the panel fixing opening 101 to which the panel 100 is fixed is small, the size of the entire panel 100 is adjusted according to the size of the panel fixing opening 101, so that the space between the leading end corner portions 100f, 100g of the adjacent engagement protrusions 100b, 100c illustrated in FIG. 21A is reduced according to the size of the panel 100.
For this reason, as illustrated in FIG. 21B, the leading end corners of the leading end corner portions 100f, 100g may interfere with each other by the variations in the measurement of the space between the adjacent leading end corner portions 100f, 100g in manufacturing. If the corners of the bent leading end corner portions 100f, 100g interfere with each other, the contact condition of the leading end corner portions 100f, 100g becomes unstable, so that it may become difficult to insert the engagement protrusions 100b, 100c into the panel fixing opening 101.
If some kind of external force acts on the engagement protrusions 100b, 100c of the panel 100 from the direction opposite the insertion direction in a state in which the panel 100 is fixed to the panel fixing opening 101, the engagement protrusions 100b, 100c easily bend in the inside direction of the panel fixing opening 101. Accordingly, if the engagement protrusions 100b, 100c bend by the external force, the locked state of the semispherical projections 100d which are locked to the neighborhood of the edge portion of the panel fixing opening 101 is easily released. The panel 100 may be thereby removed from the panel fixing opening 101.